http: add support for selecting SSL backends at runtime

diff --git a/http.c b/http.c
index 4162860ee316365091ac3978a83d2311682b8079..fedfb2a20700207fc98505f541a808db4e5176e1 100644 (file)
--- a/http.c
+++ b/http.c
@@ -155,6 +155,8 @@ static struct active_request_slot *active_queue_head;
 
 static char *cached_accept_language;
 
+static char *http_ssl_backend;
+
 size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
        size_t size = eltsize * nmemb;
@@ -302,6 +304,12 @@ static int http_options(const char *var, const char *value, void *cb)
                curl_ssl_try = git_config_bool(var, value);
                return 0;
        }
+       if (!strcmp("http.sslbackend", var)) {
+               free(http_ssl_backend);
+               http_ssl_backend = xstrdup_or_null(value);
+               return 0;
+       }
+
        if (!strcmp("http.minsessions", var)) {
                min_curl_sessions = git_config_int(var, value);
 #ifndef USE_CURL_MULTI
@@ -995,6 +1003,33 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
        git_config(urlmatch_config_entry, &config);
        free(normalized_url);
 
+#if LIBCURL_VERSION_NUM >= 0x073800
+       if (http_ssl_backend) {
+               const curl_ssl_backend **backends;
+               struct strbuf buf = STRBUF_INIT;
+               int i;
+
+               switch (curl_global_sslset(-1, http_ssl_backend, &backends)) {
+               case CURLSSLSET_UNKNOWN_BACKEND:
+                       strbuf_addf(&buf, _("Unsupported SSL backend '%s'. "
+                                           "Supported SSL backends:"),
+                                           http_ssl_backend);
+                       for (i = 0; backends[i]; i++)
+                               strbuf_addf(&buf, "\n\t%s", backends[i]->name);
+                       die("%s", buf.buf);
+               case CURLSSLSET_NO_BACKENDS:
+                       die(_("Could not set SSL backend to '%s': "
+                             "cURL was built without SSL backends"),
+                           http_ssl_backend);
+               case CURLSSLSET_TOO_LATE:
+                       die(_("Could not set SSL backend to '%s': already set"),
+                           http_ssl_backend);
+               case CURLSSLSET_OK:
+                       break; /* Okay! */
+               }
+       }
+#endif
+
        if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK)
                die("curl_global_init failed");